Tried the passive model on a custom built NR Tbird. It sounded... tinny, for lack of a better word. You know that sound that acoustic/electric guitar pickups have that electric guitar pickups just can't recreate? It was that sort of tone. I ended up swapping it very quickly for an SD SSB-4. (I was on my way to saving up for a set of Mike Lulls, but my next purchase is just going to be a Cataldo JAEbird with '66 Thunderbuckers instead.)